The invention generally relates to coated fabrics having improved durability and abrasion resistance. More specifically, the invention is directed to coated fabrics having superior abrasion resistance and color properties and good fray resistance, and a process for making such fabrics.
With developments in the transportation networks throughout the world, society has become dramatically more mobile and transient. For example, flight travel is now routine rather than infrequent, as both business and leisure travelers undertake millions of flights annually.
One change which has accompanied his progression to a more mobile society is that luggage manufacturers are being challenged to develop baggage items having increasing levels of durability in order to withstand the rigors of travel and commercial baggage handling. As will be readily appreciated by anyone who has ever watched the passenger luggage unloaded from an aircraft, the bags are often subjected to all types of detrimental forces including stacking, tossing, tumbling, crushing, tearing and the like, not to mention variations in temperatures and pressures, and inclement weather.
In fact, it is not uncommon to observe several items from a single flight which have been torn open or otherwise damaged during handling. Coupled with the fact that many travelers often overstuff their bags, luggage manufacturers face a tremendous challenge to produce products which are sufficiently durable to survive a number of trips.
In addition to requiring greater durability, consumers are also demanding that their luggage be lightweight and easy to transport. Therefore, manufacturers are challenged to provide increased product durability without significantly increasing the weight of the products.
One example of luggage manufacturers"" attempts to improve luggage durability is that the exterior fabrics used are now commonly made from high denier nylon yarns of the variety used to produce ballistic apparel. In other words, it is seen to be necessary to provide the fabrics for luggage with the same durability which would be needed to withstand the impact of a speeding bullet.
Another example of luggage manufacturers"" attempts to enhance the durability of their luggage offerings is that many manufacturers have begun coating their linings with polyurethane. While enhancing the durability significantly as compared with the conventional uncoated fabrics, the urethane coatings have been found to present some problems in and of themselves.
For one, the urethane polymer coatings are typically solvent applied. The urethane solvents are considered to be hazardous chemicals and present environmental concerns. In addition, the urethane coatings tend to alter the shade of the fabrics to which they are applied. As will be readily appreciated by those of ordinary skill in the art, this is undesirable in that it can be difficult to achieve a particular lining color desired and can be difficult to achieve consistent color, both within a single batch and from batch to batch.
Another problem associated with the conventional urethane coated lining fabrics is that they have a tendency to xe2x80x9ccrazexe2x80x9d, i.e. to develop highlights or white streaks when wrinkled during handling. In addition, the durability of such fabrics is less than what would be optimal to obtain a truly durable product.
The instant invention overcomes the deficiencies of similar fabrics by providing an improved coated fabric having superior performance capabilities as compared with the conventional urethane-coated fabrics. in. addition, the fabrics of the instant invention are coated in a manner which alters the pre-coated shade of the fabric less than about 15%, and more preferably less than about 1%. Furthermore, the fabrics of the instant invention do not require the use of hazardous chemicals, and therefore are more environmentally friendly than the conventional coated fabrics.
The fabrics of the instant invention have improved durability, with an abrasion resistance of at least about 750 cycles to failure (xe2x80x9cCTFxe2x80x9d) when tested according to ASTM D 3884. More preferably, the invention has an abrasion resistance of at least about 1000 CTF, even more preferably at least about 2000 CTF, and even more preferably at least about 2200 CTF.
In a preferred form of the invention, the fabric has an initial pre-coated color, and the coating is substantially transparent so that the coated fabric has a shade variation of less than 15% when compared with the uncoated fabric. Even more preferably, the coated fabrics have a shade variation which is less than 5%, and more preferably less than 1% different when compared with that of the uncoated fabric. Preferably, the absolute value of the difference between the depth of shade of the coated fabric and the uncoated textile substrate is less than about 0.4, more preferably less than about 0.3, and more preferably less than about 0.2. In other words, in a preferred form of the invention the change in the shade depth is at a level where it would not be visible to the human eye.
The fabrics of the instant invention also have good fray resistance, both in the warp and fill directions. Preferably, the fraying is less than 1% in each direction when tested according to a Random Tumble fray method.
In addition, the fabrics of the instant invention do not have a tendency to craze like the conventional urethane coated fabrics. Furthermore, the fabrics are desirably solvent-free, such that they are environmentally compatible.
In the following detailed description of the invention, preferred embodiments of the invention are described to enable a full and complete understanding of the invention. It will be recognized that it is not intended to limit the invention to the particular preferred embodiment described, and although specific terms are employed in describing the invention, such terms are used in a descriptive sense for the purpose of illustration and not for the purpose of limitation.
As noted above, the fabric of the instant invention desirably includes a textile substrate, to which is bonded a protective coating. The coated fabric desirably is highly resistant to abrasion, has good fray resistance, and does not exhibit a significant shade change as a result of the coating, particularly when compared with prior art coated fabric constructions.
The textile substrate can be of any variety designed to provide good strength and durability properties. In addition, the substrate will typically be selected to be relatively lightweight. In a preferred form of the invention, the textile substrate has a weight on the order of about 0.75 oz/sq yd to about 15 oz/sq yd, and more preferably less than about 5 oz/sq yd, such that the coated fabric has a weight of about 5 oz/sq yd.
The textile substrate can also be of any desired construction designed to provide the requisite functional properties. For example, the substrate can be a plain woven fabric, dobby woven fabric, twill woven fabric, weft knit fabric, warp knit fabric, weft-inserted warp knit fabric, nonwoven fabric, or the like. In a preferred form of the invention particularly useful in the manufacture of luggage linings, the textile substrate is a woven fabric, such as a dobby or a plain woven fabric.
The textile substrate can be manufactured from any types of yarns desired. In a preferred form of the invention particularly useful in the formation of lining fabrics, the substrate is made from polyester fibers or yarns, nylon fibers or yarns, acetate fibers or yarns, or blends thereof. The yarns can be textured or untextured as desired.
The coating is desirably selected to provide the substrate with a high degree of durability, without affecting its weight to a significant extent. Furthermore, the coating is desirably substantially transparent, in order that it does not significantly affect the pre-coated shade of the textile substrate. In addition, the coating also desirably resists crazing arid is environmentally compatible.
In a preferred form of the invention, the coating is substantially urethane-free and non-solvent based, and is selected from the group consisting of ethylene vinyl acetate polymers, polyesters, polyamides, suitable polyolefins such as high and low density polyethylene, metallocene, low density linear and linear low density metallocene, polybutylene, olefin copolymers such as ethylene/methyl acrylate and ethyl/butyl acrylate, ionomeric resins, and blends thereof. In a particularly preferred form of the invention, the coating is an ethylene vinyl acetate polymer. Such polymers are conventionally used as backcoatings for automotive bodycloth fabrics (e.g. those used to form the seating and panels.) However, the instant inventors surprisingly discovered that when used as a face coating on a particular substrate, ethylene vinyl acetate polymer provided a fabric having abrasion resistance superior to that obtained with urethane coatings, with comparable levels of fraying, and with dramatically less shade change than with the conventional urethane coatings.
The coating can be applied in any conventional manner. In a preferred form of the invention, the coating is applied according to a melt coating, process designed to apply thin coatings to substrates (such processes being readily understood by those having ordinary skill in the art.) For example, the process could involve an extrusion coating process, lamination process, or the like. In this way, precise metering of the coating onto the substrate can be achieved at low levels of add-on.
The coating can be applied at any desired level, but is desirably thin in order to minimize the overall weight of the product. Preferably, the coating is applied at a rate of about 0.2 oz/sq yd to about 0.8 oz/sq yd, and more preferably at about 0.5 oz/sq yd.
The fabric can be produced according to the following process: A textile substrate is produced in a conventional manner, such as by weaving, knitting or a nonwoven fabric production process. The fabric can be formed from pre-dyed fibers of yarns or the fabric can be dyed if desired to obtain a predetermined color. The fabric may also optionally be scoured and heatset to remove any excessive process chemicals from fabrication and/or dyeing and to stabilize the material. A coating is applied to the substrate such as by an extrusion coating process designed to apply a thin coating in a consistent, even manner to the fabric. The coating is then cured, to obtain the finished fabric.
In a preferred form of the invention, the fabric has an abrasion resistance of at least about 750 cycles to failure when measured according to ASTM D 3884. Even more preferably, the fabric has an abrasion resistance of at least about 1000 cycles to failure, and even more preferably, at least about 2000 cycles to failure. In a particularly preferred embodiment of the invention, the fabric has an abrasion resistance of at least about 2200 cycles to failure.
The fabric also desirably has good resistance to fraying, and in particular, fray resistance similar to that of the conventional urethane coated fabrics. For example, in a preferred form of the invention, the fabric has a fray resistance of less than 5%, and more preferably less than 1%, in each of the warp and fill directions.